Amazon is shaking up how it charges businesses that rent its cloud computing services.
Starting next month, customers will be able to pay by the second instead of by the hour, Amazon Web Services said in a blog post on Monday.
In charging by tiny increments, Amazon is leapfrogging two rivals that had previously leapfrogged it. Both Google and Microsoft have offered per-minute pricing for their competing services since 2013.
Amazon, the market leader in cloud computing, declined to budge on its per-hour pricing increment—until now.
To back up, many companies run some of their business software on shared public cloud data centers operated by Amazon (AMZN), Google (GOOGL), and Microsoft (MSFT) instead of spending the money to maintain their own data centers.
One supposed benefit of the cloud model is that customers pay only for the resources they use. If they operate their own data centers, on the other hand, they’re on the hook for all of that equipment, real estate, and power, whether they run their computers at full capacity or not.
Lydia Leong, vice president and analyst at market research firm Gartner (IT), said that per-second pricing is a first in this growing cloud computing category.
Amazon’s new pricing applies to both its computing capabilities, known as the Elastic Compute Cloud (or EC2) service, as well as the storage (called Elastic Block Storage or EBS) associated with those computing building blocks.
Amazon and its rivals are finding ways to divvy up cloud computing power in interesting ways. Amazon’s Lambda service, for example, lets software developers set up actions that automatically trigger when a certain event occurs. Say, a user clicks on a website button to upload a photo, Lambda fulfills that request and then shuts off so the developer is only charged for that small portion of time it takes Lambda to fulfill the request.
Get Data Sheet, Fortune’s daily tech newsletter.
The new price takes effect starting Oct. 2, and applies just to software running on Linux operating systems, and not Windows (Amazon offers both options on its cloud.)